Introduction

Uses for Timolol

Ocular Hypertension and Glaucoma

Reduction of elevated IOP in patients with open-angle glaucoma or ocular hypertension.104105106107 Used alone or in conjunction with another IOP-lowering drug (e.g., latanoprost, a carbonic anhydrase inhibitor).104105106107108

Fixed-combination preparation containing timolol maleate and dorzolamide hydrochloride used to reduce elevated IOP in patients with open-angle glaucoma or ocular hypertension who have not responded adequately (i.e., failed to achieve target IOP as determined after multiple measurements over time) to a topical β-adrenergic blocking agent.108

Timolol Dosage and Administration

Administration

Ocular Administration

If more than one ophthalmic drug is used, administer the drugs at least 10 minutes apart.104106

Invert and shake containers of timolol ophthalmic gel-forming solution once just prior to administration of each dose.106

Dosage

Available as timolol maleate or timolol (as the hemihydrate); dosage is expressed in terms of timolol.104105107

Adults

Ocular Hypertension and Glaucoma

Ocular Administration

Timolol ophthalmic solution: initially, 1 drop of a 0.25% solution in the affected eye(s) twice daily.104105107 May increase dosage to 1 drop of a 0.5% solution in the affected eye(s) twice daily if necessary.104105107 May then reduce dosage to 1 drop of the effective strength in the affected eye(s) once daily if satisfactory IOP is maintained.104105107

Timolol ophthalmic gel-forming solution: 1 drop of a 0.25 or 0.5% solution in the affected eye(s) once daily.106

Warnings/Precautions

Warnings

Cardiovascular Effects

Severe cardiac reactions, including death associated with cardiac failure, have been reported in patients receiving systemic or topical (ocular) timolol.104105106107 Discontinue therapy at the first sign or symptom of cardiac failure.104105106107

Respiratory Effects

Severe respiratory reactions, including death resulting from bronchospasm, have been reported in patients receiving systemic or topical (ocular) timolol.104105106107

Patients with mild or moderately severe COPD (e.g., chronic bronchitis, emphysema), bronchospastic disease, or a history of bronchospastic disease (other than bronchial asthma or a history of bronchial asthma, in which condition timolol is contraindicated) generally should not receive β-adrenergic blocking agents.104105106107

Diabetes Mellitus

β-Adrenergic blocking agents may mask signs and symptoms of acute hypoglycemia; administer with caution in patients subject to spontaneous hypoglycemia and in diabetic patients (especially those with labile diabetes) who are receiving hypoglycemic agents.104105106107

Sensitivity Reactions

Patients with a history of atopy or of a severe anaphylactic reaction to a variety of allergens may be more reactive to repeated accidental, diagnostic, or therapeutic challenges with such allergens while taking β-adrenergic blocking agents; such patients may be unresponsive to usual doses of epinephrine used to treat anaphylactic reactions.104105106107

Exact mechanism of action not fully elucidated; tonography and fluorophotometric studies suggest that reduced aqueous humor formation is the principal effect.104105106107 A slight increase in outflow facility observed in some studies.104105106107

Tolerance may develop with prolonged use; however, IOP-lowering effect maintained for at least 3 years of continuous use in some patients.b

Advice to Patients

Importance of learning and adhering to proper administration techniques to avoid contamination of the product.104105106107 If more than one topical ophthalmic drug is used, importance of administering the drugs at least 10 minutes apart.104106

When an ophthalmic preparation that contains benzalkonium chloride is used, importance of removing soft contact lenses prior to administering a dose and for at least 15 minutes after administration.104

Advise patients to consult a clinician immediately regarding the continued use of ophthalmic preparations if an intercurrent ocular condition (e.g., trauma, infection) occurs.104105106107

Importance of patients informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as concomitant illnesses.104105106107

Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.104105106107

Importance of informing patients of other important precautionary information.104105106107 (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.